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Evaluation of LNPs as an emulsion stabilizer in Pickering emulsions for cosmetic applications : master's thesis
Nicole Blažević, 2022, master's thesis

Abstract: The growing concern about the environmental impact and human health risk related to the excessive use of synthetic ingredients in cosmetics and topical formulations calls for the exploration of safe and sustainable natural alternatives. Kraft lignin is a polyphenolic compound generated as a by-product from the kraft pulping process in large quantities annually worldwide. In addition to its commercial availability, its structural features and diverse functional properties make it worth to be considered as a bio‐active ingredient for cosmetic and personal care products. The intrinsic limitations of its native form for the development of high-performance products can be overcome by morphology control through particle size reduction to nanoscale. Therefore, in this research lignin nanoparticles were evaluated for the stabilization of Pickering emulsions. First, a screening of conditions and ingredients was carried out to assess the most suitable parameters for the synthesis of emulsions. The synthesis of final Pickering emulsions was performed using a rotor-stator homogenizer followed by ultrasound. The quality of emulsions stabilized with LNPs were assessed in relation to the emulsification process parameters and ingredients used in the formulation. In generenal, higher concentration of LNPs and volume of oil favoured the emulsion stability. Sun protection factor test showed promising values for application of LNPs in the sunscreen field. We compared the SPF of emulsions prepared with orange, coconut, and paraffin oil. The results showed that emulsion with orange oil had the highest SPF at 16.5, with coconut oil it was 8.8, and the lowest for emulsion with paraffin oil which was 1.7.
Keywords: lignin, LNPs, oils, Pickering emulsions
Published in DKUM: 05.09.2022; Views: 941; Downloads: 0
.pdf Full text (6,36 MB)

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Vpliv zamreženja porozne poli(akrilne kisline) na absorptivne lastnosti : diplomsko delo univerzitetnega študijskega programa I. stopnje
Nicole Blažević, 2020, undergraduate thesis

Abstract: V diplomski nalogi z naslovom Vpliv zamreženja porozne poli(akrilne kisline) na absorptivne lastnosti smo sintetizirali porozno poli(akrilno kislino). Za pridobivanje poroznih materialov obstaja več različnih tehnik, mi smo se posluževali polimerizacije kontinuirne faze emulzije z visokim deležem notranje faze (HIPE polimerizacija). Pri naši sintezi je vlogo monomera igrala akrilna kislina, kot zamreževalo pa smo uporabljali N,N ́-metilenbisakrilamid (MMBA). Za nastanek emulzije so nujno potrebni še iniciator, mi smo uporabljali amonijev persulfat (APS), surfaktant, mi smo uporabljali Triton X-405, ter redukcijsko sredstvo, mi smo uporabljali tetrametiletilendiamin (TEMED). Reakcija je potekala po verižni radikalski polimerizaciji. Emulzija, ki smo jo pripravili je bila tipa olja v vodi. Kot notranjo fazo smo uporabljali topilo toluen. Materiale pred karaterizacijo je bilo potrebno očistiti z ekstrakcijo v Soxhletovem aparatu, kjer smo odstranili notranjo fazo, pri tem pa smo uporabljali topilo metanol. Sintetizirali smo več različnih materialov in sicer pri enem nismo dodali vodne raztopine NaOH, pri ostalih treh pa smo spreminjali stopnjo zamreženosti, ki je varirala med 10 %, 25 % in 50 %. Po sintezi smo del materiala pustili v metanolu, del smo ga pa dali sušiti v vakuumski sušilnik. Nato smo opazovali sestavo in absorptivno zmogljivost za vodni medij. Absorptivno zmogljivost smo preverjali pri materialu, ki se ni sušil v vakuumskem sušilniku, in sicer v deionizirani vodi. Pri materialih, ki so se sušili v vakuumskem sušilniku smo preverjali absorptivno zmogljivost v destilirani vodi, 0.1 M raztopini NaOH in 0.1 M raztopini HCl. Ugotovili smo, da se materili, ki imajo višjo stopnjo zamreženosti slabše absorbirajo kot materiali z nižjo stopnjo zamreženosti. Na samo absorptivnost vpliva tudi prisotnost baze v sami sestavi. Če je prisotna baza, nastane material z nabito hidrofilno skupino COONa, ki ima dobre absorptivne zmogljivosti. Če pa ni prisotna baza, nastane porozni material s kislinsko skupino COOH, ki ima slabše absorptivne zmogljivosti.
Keywords: emulzija, zamreženost, absorptivne lastnosti, HIPE, poli(akrilna kislina)
Published in DKUM: 08.10.2020; Views: 1494; Downloads: 117
.pdf Full text (1,63 MB)

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